ARGUMENTS

Specifies the colormap entries to be allocated. You can pass
AllocNone
or
AllocAll.
Specifies the colormap that you want to create, copy, set,
or destroy.
Specifies the connection to the X server.
Specifies a visual type supported on the screen. If the visual
type is not one supported by the screen, a
BadMatch
error
results.
Specifies the window on whose screen you want to create a
colormap.

DESCRIPTION

The
XCreateColormap
function creates a colormap of
the specified visual type for the screen on which the specified window resides
and returns the colormap ID associated with it. Note that the specified window
is only used to determine the screen.

The initial values of the colormap entries are undefined for the visual
classes
GrayScale,
PseudoColor, and
DirectColor. For
StaticGray,
StaticColor, and
TrueColor, the entries have defined values,
but those values are specific to the visual and are not defined by X. For
StaticGray,
StaticColor, and
TrueColor, alloc must be
AllocNone, or a
BadMatch
error results. For the other visual classes, if alloc is
AllocNone, the colormap initially has no allocated entries, and
clients can allocate them. For information about the visual types, see section
3.1.

If alloc is
AllocAll, the entire colormap is allocated
writable. The initial values of all allocated entries are undefined. For
GrayScale
and
PseudoColor, the effect is as if
an
XAllocColorCells
call returned all pixel values from
zero to N - 1, where N is the colormap entries value in the specified
visual. For
DirectColor, the effect is as if an
XAllocColorPlanes
call returned a pixel value of zero and red_mask,
green_mask, and blue_mask values containing the same bits as the corresponding
masks in the specified visual. However, in all cases, none of these entries
can be freed by using
XFreeColors.

The
XCopyColormapAndFree
function creates a colormap
of the same visual type and for the same screen as the specified colormap
and returns the new colormap ID. It also moves all of the client's existing
allocation from the specified colormap to the new colormap with their color
values intact and their read-only or writable characteristics intact and frees
those entries in the specified colormap. Color values in other entries in
the new colormap are undefined. If the specified colormap was created by the
client with alloc set to
AllocAll, the new colormap is
also created with
AllocAll, all color values for all entries
are copied from the specified colormap, and then all entries in the specified
colormap are freed. If the specified colormap was not created by the client
with
AllocAll, the allocations to be moved are all those
pixels and planes that have been allocated by the client using
XAllocColor,
XAllocNamedColor,
XAllocColorCells, or
XAllocColorPlanes
and that have not been
freed since they were allocated.

XCopyColormapAndFree
can generate
BadAlloc
and
BadColor
errors.

The
XFreeColormap
function deletes the association
between the colormap resource ID and the colormap and frees the colormap storage.
However, this function has no effect on the default colormap for a screen.
If the specified colormap is an installed map for a screen, it is uninstalled
(see
XUninstallColormap). If the specified colormap is
defined as the colormap for a window (by
XCreateWindow,
XSetWindowColormap, or
XChangeWindowAttributes),
XFreeColormap
changes the colormap associated with the window to
None
and generates a
ColormapNotify
event. X
does not define the colors displayed for a window with a colormap of
None.

XFreeColormap
can generate a
BadColor
error.

STRUCTURES

The red, green, and blue values are always in the range 0 to 65535 inclusive,
independent of the number of bits actually used in the display hardware. The
server scales these values down to the range used by the hardware. Black is
represented by (0,0,0), and white is represented by (65535,65535,65535). In
some functions, the
flags
member controls which
of the red, green, and blue members is used and can be the inclusive OR of
zero or more of
DoRed,
DoGreen, and
DoBlue.

DIAGNOSTICS

The server failed to allocate the requested resource or server
memory.
A value for a Colormap argument does not name a defined Colormap.
An
InputOnly
window is used as a Drawable.
Some argument or pair of arguments has the correct type and
range but fails to match in some other way required by the request.
Some numeric value falls outside the range of values accepted
by the request. Unless a specific range is specified for an argument, the
full range defined by the argument's type is accepted. Any argument defined
as a set of alternatives can generate this error.
A value for a Window argument does not name a defined Window.